The present invention is directed to medically implantable electrical connectors and is more particularly directed to medical connectors which have tailored connect and disconnect forces. Such connectors can be used in a number of medical devices such as, for example, pace makers defibrillators, and neuro-stimulators. Medically implantable electrical connectors are adherently different than a vast majority of other electrical connections due to the environment and critical nature of their use. Such medical connectors must not only be made of materials suitable for implanting within a body, but also must provide positive and unvarying conductivity thereacross in order to insure reliability of a functioning medical device.
Heretofore, implantable electrical connectors have utilized a lead wire, or pin, and a housing with the lead wire removably fixed to the housing by a set screw. It should be appreciated that such set screws are small, thus losable. In addition, a set screw is very torque sensitive and requires a tool for installation.
The present invention provides for an implantable electrical connector with reduced resistivity and reduced resistivity variability under static and dynamic loading without the necessity of an installation tool.
A medically implantable electrical connector in accordance with the present invention generally includes a housing having a bore with an internal groove therein along with a garter spring disposed in a groove.
A pin is sized for insertion into the housing bore and may include an external groove for capturing the spring in order to removably latch the pin within a housing bore.
Reduced resistivity across the connector including the housing spring and pin is achieved through the use of a shaped V-groove and by forming the housing, spring and pin from a combination of medically implantable materials in order to control the resistivity. Preferably, the spring is formed from platinum iridium.
In one embodiment of the present invention, the pin does not include the external groove and the housing groove is a V-groove. More particularly, the V-groove may have an included angle of about 135xc2x0 and in the embodiment including the pin groove a cross-section of the pin groove may include a flat center portion subtended by angled sides. As hereinafter described a V-groove with a radial spring provides for greater conductivity of the connector with enhanced conductivity stability than a flat bottom groove with a radial spring.
Still more particularly, the angled sides may be disposed at about a 45xc2x0 with a flat center.
In all of the embodiments of the present invention, one of the housing pin, or spring is preferable formed from platinum iridium with the most preferred being a platinum iridium spring. The remaining components, namely the housing and pin may be formed from MP35N or titanium grade-5 or stainless steel.
Other embodiments of the present invention include a connector with a housing V-groove and a radial garter spring, or a connector with a housing flat groove and an axial spring. The axial spring provides for greater conductivity with a housing with flat grooves in view of the fact that the axial spring motion produces a scraping action that removes oxides thus decreasing resistivity.